Hydraulic brake mechanism



. Dec. 9, 1930. c. c. scHMlD'r ET Al. 1,784,547

HYDRAULIC BRAKE MECHANISM Filed May 5, 1928 5 Sheets-Sheet l Il" if Dec.9, 1930. c. c. scllMl-DT T AL l 1,784,547

HYDRAULIC BRAKE MEGHANI SM Filed May 5. 1928 5 Shxeet's--Sheec 2 Fly.

eth1/nui Dec- 9, 1930 l c. c. s-cHMlD-r ET AL 1,784,547

HYDRAULIC BRAKE MECHANISM Filed May 5. 1928 5 Sheets-Sheet 5 INVENTQRQAT I'ORNE:Y

Patented Dec. 9, 1930 UNITED STATES PATENT OFFICE CLARENCE CARL SCHMIDT,OF REYNOLDSBURG, AND JOHN LOUIS RICHTER, OF BEXLEY, OHIO HYDRAULIC BRAKEMECHANISM Application filed `IMay 5, 1928. Serial No. 275,365.

This invention relates to improvements in hydraulic braking systemsespecially adapted for automobiles.

An object of the present invention is to e provide means to compensatefor pressure in excess of the amount necessary to eectually operatethebrakes, and thus reduce danger of bursting the reserve reservoir, anddanger of blowing out the packings of the system w connections.

Another object of the invention is the provision of means for effectinga harder pressure upon the brake drums of the rear wheels of a fourwheel system when the brakes are l initially applied, and for thereafterequal` izing the pressure and eliminating danger of the front wheelsresponding to the braking action before the rear wheels.

Another object of the invention is the provision of means forselectively.cutting out either of the (front wheel brakes, or the rearwheel brakesAi-n the event of leakage or damgAnotlier object of theinvention is the provision of means whereby the braking eti'ect of thesystem may be tested while the vehicle is stationary.

With the above and other objects in view, the invention further includesthe following novel features and details of construction, to

be hereinafter more' fully described, illus- .trated in the accompanyindrawings and pointed out in the appended claim.

In the drawings Figure 1 is an elevation of a compensating or equalizingdevice constructed in accordance with the invention.

Figure 2 is a longitudinal sectional view of the same.

Figure 3y is an lend view.

Figure 4 is a similar view looking at the opposite end of the device.

Figure 5 is a detail view of the spacing V member.

"Figure 6 is a face view of the' plunger.

Figure 7 is a 1ike view of the plunger carried disk. A y

Figure 8 is an elevation ofthe equalizing or gompensating deviceconnected with the distributing tubes and showing the pressure gauge. v

Figure 9 is a detail elevation of one of the controlling valves.

Figure 10 is a diagram illustrating the manner of connecting thecompensating cylinder in the system.

Referring to the drawings in detail wherein like characters of referencedenote corresponding parts, the reference character 11 indicates therear brake drums and 12 the front brake drums of the braking mechanismof an automobile. These drums are provided with braking elements 13which are hydraulically operated, the reference character 14 indicatingVthe braking cylinders for these elements. Fluid under pressure issupplied to the braking cylinders from a master orbrake operatingcylinder 15. This cylinder houses a piston 16 whose rod 17 is connectedin a suitable manner with the brake pedal so that the fluid wit-hin thecylinder and Within the distributing tubes 18 of the -system willprovide a sutiicient pressure to operate the brakes. The foregoingconstruction may be of the usual or any preferredtype.

In carrying out the present invention use is made of a compensating orequalizing cylinder 19. This cylinder is provided with an inlet port 20which is connected by means of a pipe or tube 21 .with the brakeoperating or master cylinder 15. The cylinder 19 is also provided withspaced distributing ports 22 which are connected with the distributingpipes 18. A pressure gauge 23 is connected with the port 20 by -means ofa tube or pipe 24:.

The cylinder 19 may be carried by a suit-4 able bracket 25 and mountedin a suitable position, and movable within this cylinder is a plunger26.. This plun er has detachably connected thereto a disk 2 and for thispurpose this disk is provided with a headed eX- tension 28 which isengaged within a keyhole socket 29 provided in the end of the plunger26. Also located within the cyllnder 19 is a head 30. and this head andthe plunger 26 may be provided with annular oil grooves 31. The plunger26 and the head 30 are hol# low and receive the opposite endsof a springshank 36. One end of this shank issquarey as at 37 to receive a`suitable tool, ile the opposite end bears upon a plate or disk 38 whichis in contact with the head/ 30.

` guide for the rod.

By adjusting the shank 36, the position ofthe head 30 may be regulatedso that the tension of the spring will be adjustedto controlthe-movement of the plunger 26. lock nut 39 may be arranged to hold theshank in adjusted position.

The plunger 26 is provided with a socket 40 which receives a ball 41provided at one end of a rod 42. This rod extends through the head 30and into a socket 43 provided in the shank 36 so that the latterprovides' a Controlling valves 44 and 45 are provided in thedistributingI pipes 1B.

The system being supplied with iu1d,op eration of the piston 16 willbuild up pressure-in the system roportionate to the de- I brakes thanthe front brakes,

gree of movement o said piston. The valves 44 and 45 are so adjustedthat initially, a greater pressure will be supplied to the rear afterwhich all of thev brakes will be equally applied.

This will prevent operation of the frontv brakes prior to the operationof the rear brakes. This also eliminates danger of failure of the rearbrakes to operate in advance of the front brakes due to lack of tractionsurface for the rear Wheels, as when the vehicle strikes a bump or rutas the brakes are applied. Should excessive pressure be used in applyingthe brakes, this excess pressure v'will be taken care of bythecompensating cylinder, As theliuid passes thr ugh. the fluid chamber34to the distrlbuti g pipes, excess pressure willforce the plunger 26tochanges in its form, proportions and minor details of construction andthe right is herein reserved to make such changes as properly fallwithin the scope of the appended claim. f

Having described the invention what is claimed is A hydraulic brakingsystem for vehicles comprising a pair of rear Huid operated brakingelements and a pair of front iiuid operated braking elements, conduitsfor conducting liquid to said braking elements, acylinder having' a pairof ports in one end, one of said ports being connected to the frontliquid conduit and the other connected to the rear liquid conduit,valves in said conduits having means for indicating the size of theopening from the conduits to the saidcylinder, a piston in saidcylinder, a spring on one side of said piston, the other side of thepiston being exposed to the liquid in the system, means for varying thetension of the spring, a second cylinder having a manually operablepiston movable therein, a fluid conduit from the said last-namedcylinder to the first-named cylinder for applying pres' sure to thelatter, and means for indicating tures. v. A-

CLARENCE CARL SCHMIDT. JOHN LOUIS RICHTER.

afiix our signa- Ward the opposite end of the cylinder, the

degree of movement being proportionate to the amount of pressure.

The chamber v34 will thus in eiect expand proportionate to the amount ofpressure 1n excess of that required to properly apply the brakes. Byadjustingv the'shank 36, the position of the head 30 may be regulated soas to controlthe point at which the plunger 36 ,will act.' This willprevent damage to the master cylinder or the connections in the tubeline of the system, and reduce danger of leaks.-

The efficiency of the brakes may be tested vwhen the vehicle is at astandstill, by operating the-brake pedal andholding the same

